physical development, ages 11 to 14 years

overview

adolescence is a time of rapid growth in height and weight and of physical changes throughout the body. most of these changes happen near the time of puberty. in canada and the united states, puberty usually starts between the ages of 9 and 13.

in females:

• breast buds (slight raising and enlargement of the nipple area) are one of the first signs of puberty. pubic hair usually starts growing around the same time.
• existing body fat shifts to the pelvis, breasts, and upper back.
• early puberty is usually a time of rapid growth. then growth slows down with the first menstrual period. females reach their approximate adult height around 16 years of age.
• periods usually start sometime between ages 11 and 14. they can start as early as age 9 or up to age 15.

in males:

• the first sign of puberty is that the testicles get larger. this is followed by the growth of pubic hair and by penis lengthening.
• hair growth usually starts on the upper lip. it gradually reaches the cheeks and then the chin area.
• the amount of body fat increases during puberty. it's common to develop breast tissue during early-to-middle puberty. this is called gynecomastia. it usually goes away in 6 months to 2 years.
• the height spurt occurs after other signs of puberty have developed. while they lag in height in early adolescence, males typically end up being taller than females. this is because after growth starts, males grow at a faster rate and for a longer period of time. they reach approximate adult height at about 18 years of age.

growth in body parts may occur out of sync with each other. for example, the nose, arms, and legs may grow faster than the rest of the body. other physical development during puberty usually includes:

• bone growth. this increases your child's height.
• an increase in skull bone thickness. the forehead becomes more prominent, and the jaw grows forward.
• weight gain. a child's weight almost doubles during adolescence.
• an increase in the size of organs. the heart doubles in weight, and lung size increases.

the surging hormones related to puberty often stimulate the sex drive. it's normal to masturbate in private. hormones may also trigger episodes of difficult behaviour, such as challenging parents and other authority figures.